Re: decreases in MTU

Steve Deering <> Mon, 05 March 1990 19:45 UTC

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Date: 5 Mar 1990 10:47-PST
From: Steve Deering <>
Subject: Re: decreases in MTU
To: Philippe Prindeville <philipp@Gipsi.Gipsi.Fr>
Cc: mtudwg
Message-Id: <90/03/05>
In-Reply-To: Philippe Prindeville's message of Mon, 5 Mar 90 182331 -0100

>	It would (should?) not be hard to mandate that all sub-576 MTU paths
>	be the first to employ the new type of Can't Fragment message.

It would be just as easy to mandate that *all* gateways employ the new
type of Can't Fragment message.  However, mandating does not make it so.

>	Anyway, there can't be all that many such paths (I hope).  The only
>	one I can think of would be ARCnet (with a 511-byte MTU)...

Van's new RFC on TCP header compression recommends small MTUs for low
speed (i.e., 19,200 bps and lower) links, to give reasonable interactive
responsiveness.  The DARPA PR (packet radio) net has a sub-576 MTU -- is
it still in use in the Internet?  What's the MTU for IP on AppleTalk?